Pt/ZSM-35/MCM-49催化剂上H_2选择还原NO

NO Selective Reduction by H_2 over Pt Supported ZSM-35/MCM-49

将共结晶分子筛作为催化剂载体应用于富氧条件下的氮氧化物消除反应.在体积分数为0.1%NO,0.5%H2,6.7%O2,He气为平衡气,反应空速8×104h-1条件下对比考察了Pt/ZSM-35/MCM-49,Pt/ZSM-35和Pt/MCM-49催化剂在氢气选择催化还原氮氧化物反应中的活性.结果表明,Pt/ZSM-35/MCM-49催化剂上的活性较其它2个催化剂有一定程度的提高,NO转化率最高达到84%,N2选择性最高达到74%.通过X射线衍射(XRD)、氨气程序升温脱附(NH3-TPD)、氢气程序升温还原(H2-TPR)、CO吸附红外和原位漫反射红外对3种催化剂进行了表征.结果发现,Pt/ZSM-35/MCM-49催化剂活性的提高源于共结晶有利于生成和稳定重要的中间物种——氨物种.

Composite zeolite was used as support in NOx elimination. The catalytic performances of Pt/ZSM-35/MCM-49, Pt/ZSM-35 and Pt/MCM-49 were studied on the condition of 0.1%NO, 0.5%H2, 6.7%O2, He as balance gas and GHSV=8×104 h-1. The results show that the activity of Pt/ZSM-35/MCM-49 is higher than the other two catalysts： the maximum NO conversion and N2 selectivity reaches 84% and 74%, respectively. XRD, H2-TPR, CO adsorption and in situ FTIR were employed to characterize these three catalysts. The results indicate that the enhancement of activity comes from the co-crystallization, which is benefit for the formation and stabilization of key intermediates, ammonium species.